KING OF PRUSSIA, Pa. — Police are investigating after a Pennsylvania mother found a spiteful note written on her car window during a trip to take her terminally ill son to visit Santa.

Nancy Coyne tells WTXF-TV she parked in the disability area to take her 7-year-old son Garrett to see Santa at King of Prussia Mall.

Upon her return, Coyne says she found a message written on the car window in red lipstick that read, “UR not handicap (sic).”

The station reported Wednesday that Garrett has been diagnosed with Batten disease. The disease has left the child blind, and he is slowly losing his motor skills. Most children with the disease don’t live to their teen years.

Coyne says she used a legal parking placard. A mall spokesman says they are helping police investigate.